The term Tick-borne Spotted Fevers is a catch-all term used to describe illnesses caused by ticks infected with Rickettsia bacteria. Rickettsial infections are zoonoses – animal infections that can spread to humans – transmitted by Rhipicephalus, Ixodes, Amblyomma, Hyalomma, Haemaphysalis, and Dermacentor ticks who feed on deer, birds, rodents, and dogs. Humans become ill when they get bitten by infected ticks (typically in the immature or nymph stage of their life cycle). Due to climate change, tick populations are moving further north in latitude.
African Tick-Bite Fever, Mediterranean Spotted Fever, and Rocky Mountain Spotted Fever are some of the tick-borne infections that can affect travellers.
Rickettsia bacteria are present worldwide. Many tick species are moving further north in latitude due to climate change. Infections tend to be seasonal when ticks are most active from spring to fall. Travellers involved in outdoor activities in forested areas are at risk, including campers, hikers, and hunters. Brushing against vegetation or walking in city parks known to have infected ticks can also put a person at risk. Rickettsial infections are not transmitted from person to person.
Rickettsial infections are characterized by flu-like symptoms and a rash that usually appear 5 to 14 days after exposure. Initial symptoms include fever accompanied by headache, muscle pain, and sometimes nausea, vomiting, diarrhea, and cough. A red rash can develop and black tissue, also known as an 'eschar', forms at the site of the tick bite. Some people may not exhibit these symptoms, making spotted fevers difficult to diagnose. Rickettsial spotted fever infections can range from mild to severe and are treated with antibiotics.
In the case of Rocky Mountain Spotted Fever symptoms can be severe and fatal if untreated. Complications can occur as a result of blood vessel damage which causes brain swelling, heart, lung, and kidney failure, and gangrene on fingers and toes.
Travellers who participate in hiking, camping, or similar outdoor activities in wooded regions of endemic areas should take measures to prevent tick bites. There is no preventive medication or vaccine against rickettsial infections.
Information last updated: March 22, 2019